Fever in the Tropics
Tom D. Thacher, MD
thacher.thomas@mayo.edu
Learning Objectives
To understand the syndromic approach to fever in the tropics
To identify common causes of 8 febrile syndromes
Disease burden
Infectious disease is a larger proportion of disease burden in developing
countries
Chronic, non-communicable disease is a greater burden in developed
countries (epidemiological transition)
Africa has the greatest proportion of infectious disease burden
Context of fever
Age – child/adult
Geography – region of the world, elevation
Season – rainy/dry
Duration of fever – acute/chronic
Malnutrition – cause or consequence of infection
Immune status – immunizations, HIV
Exposures – insect vectors, water source, HIV, TB
Syndromic approach
Framework to a differential diagnosis in the absence of laboratory and
imaging
Combination of clinical symptoms associated with fever
Not an etiological approach
Based on clinical symptoms and clinical judgment rather than diagnostic
tests
Empiric treatment for the most likely infections that fit the clinical
syndrome
Diagnosis often confirmed by response to treatment
Common fever syndromes
Under 5 mortality is 20% in African children
Five febrile diseases account for 2/3 of child deaths in Afric
 Malaria
 Pneumonia
 Diarrhea
 HIV
 Measles
Fever Alone
Malaria
40% of world’s population at risk
Greatest killer of children in endemic regions
Most severe in children, pregnant women, travellers
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Repeated infections lead to partial immunity
Blood smear or rapid diagnostic tests for confirmation
Clinical manifestations
 Headache
 Pallor – due to severe hemolytic anemia
 High output heart failure
 Cerebral malaria – impaired mental status, convulsions, coma
 Labored breathing – acidosis, heart failure
 Splenomegaly – spleen rate used to assess endemicity
Typhoid fever
Salmonella typhi ingested in contaminated water or food
Consider after failure of antimalarial treatment or negative blood film for
malaria parasites
Symptoms
 Sustained high fever >1 week duration
 Headache
 Apathy, psychosis
 Abdominal pain
 Constipation
 Splenomegaly
Positive blood culture
HIV
Prevalence 5-35% in African countries
Persistent fever >1 month in young adult accompanied by weight loss
HIV serology to confirm
If toxic appearing, consider salmonella sepsis
Dengue
Asia, So. America – a leading cause for hospitalization in Asia
Clinical manifestations
 Marked myalgia, eye pain – “breakbone fever”
 Rash – sea of red with islands of normal skin
 ↓ WBC, ↓ platelets
 Dengue shock syndrome – increased vascular permeability and
plasma leakage resulting in pulmonary edema, pleural effusion,
ascites.
No specific drug treatment – supportive treatment
Leptospirosis
Acquired by exposure to fresh water contaminated by animal urine
Clinical manifestations
 Rash
 Aseptic meningitis
 Jaundice
 Clinical clue: conjunctival injection in 1/3 of cases
Treatment - doxycycline
Rickettsia
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Fever, headache, and myalgia
Clue: tick exposure, painless eschar
Rickettsia africae is a cause of African tick-bite fever
Scrub typhus is transmitted by chiggers (trombiculid mites) in areas of
heavy scrub vegetation
Treatment - doxycycline
Relapsing fever
Borrelia transmitted by lice or soft-bodied tick bite, often in conditions of
severe poverty like refugee camps
Treatment - doxycycline
Other viral illnesses
Fever typically lasts <1 week
Neurologic Syndromes
Fever, headache, altered mental status, convulsions, coma
Cerebral malaria
Meningitis
Bulging fontanel in infants <12 mo, nuchal rigidity in older children
S. pneumoniae or H. influenza in children
N. meningitidis (serogroup A) in African meningitis belt – dry season
epidemics every 8-12 years.
Eosinophilic meningitis due to Angiostrongulus cantonesis in SE Asia,
Pacific, Caribbean
Purpura in cases of N. meningitidis
Lumbar puncture with CSF gram stain and cell count. WBC>1 phf
considered meningitis.
Encephalitis
Identified by geography and exposures.
Often indistinguishable clinically from meningitis
May present as fever with vomiting due to increased intracranial pressure
Rabies – history of animal bite in preceding 3 months
Japanese encephalitis – SE Asia
West Nile encephalitis – Africa, Asia
Trypanosomiasis (sleeping sickness) – Tsetse fly exposure in Africa, rare
HIV
Chronic Meningitis – TB, cryptococcal. Nuchal rigidity, cranial nerve
palsies, altered mental status
Toxoplasmosis – focal deficits or seizures suggestive of possible mass
lesion
HIV dementia – chronic presentation
Abdominal Syndromes
Fever, abdominal pain, diarrhea
Typhoid
Can progress to perforation of the ileum – constipation, peritoneal signs.
Upright CXR can identify free intraperitoneal air, indicating need for
laparotomy.
Treated with a fluoroquinolone
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Infectious colitis
Bloody, mucoid stools and tenesmus
Organisms: Shigella, E. coli, salmonella, campylobacter, ameba
Stool microscopy can confirm leukocytes, amebic cysts or trophozoites
Worms typically do not cause a febrile illness
Treatment – fluoroquinolone antibiotic
Amebic liver abscess
Hepatic tenderness and spiking fevers, without significant jaundice.
CXR can show elevation of right hemidiaphragm and atelectasis.
Ultrasound can confirm diagnosis.
Treatment – tinidazole or metronidazole
Abdominal TB
Abdominal distension and ascites, associated with fever and weight loss.
Appendicitis, pyelonephritis
Gallstones, kidney stones, and diverticulitis are uncommon in most
tropical regions
HIV
Commonly presents with fever and chronic diarrhea, associated with
weight loss.
HIV can also cause pancreatitis
Pulmonary Syndromes
Fever, cough, dyspnea
Pneumonia
Usually due to S. pneumoniae or H. influenza in children
Treatment with amoxicillin or cotrimoxazole is often used
Integrated Management of Childhood Illness (IMCI) – clinical diagnosis
 Increased respiratory rate
o ≥60 if age < 2 mos.
o ≥50 if age 2-12 mos.
o ≥40 if age 12 mos. to 5 years
 Lower chest retractions
Tuberculosis
1/3 of the world's population is currently infected with the TB bacillus, and
5-10% of those will develop tuberculous disease.
Pulmonary TB is the most common opportunistic infection in patients with
AIDS. About 1/3 of the cases of PTB are related to underlying HIV
infection.
Tuberculosis is the leading infectious cause of death worldwide.
BCG vaccine confers little protection against pulmonary TB, but makes
skin tests a less reliable means of diagnosis
Presentation: chronic cough, fever, night sweats, hemoptysis, weight loss,
anemia
Diagnosis by sputum smear acid-fast staining, 3 smears
CXR findings
 Hilar adenopathy – children,
 Pulmonary cavities – most infectious, positive sputum smear
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 Pleural effusion – pleural fluid with lymphocyte predominance
 Diffuse small nodules – military TB, add prednisone to treatment
HIV
Frequently presents as pneumonia or TB in adults
Lymphocytic interstitial pneumonia (LIP) in children – chronic, diffuse,
bilateral interstitial infiltrates on CXR, unresponsive to antibiotics
Rash Syndromes
Fever and skin rash
Measles
Generalized rash with conjunctivitis, coryza (runny nose), and cough
HIV
Herpes zoster
Oral candidiasis
Kaposi sarcoma
Stevens-Johnson syndrome – sulfonamides, thiacetazone
Pruritic papular dermatosis
Dengue
Other viruses
Hemorrhagic Syndromes
Hematemesis, melena, epistaxis, petechiae, purpura, puncture site
bleeding
Infectious to health care provider – blood and body fluid precautions
Ebola, Lassa, Marburg
Sore throat is a prominent symptom
Yellow fever
Deep jaundice, liver failure, coagulopathy
Dengue hemorrhagic fever
Relapsing fever
Musculoskeletal Syndromes
Fever with joint or bone pain
Sickle cell disease
Dactylitis – painful swelling of the proximal phalanges in infant
Vaso-occlusive crisis – bone pain, abdominal pain, fever
Septic arthritis
Osteomyelitis
Acute osteomyelitis is often associated with septic arthritis in children
Chronic osteomyelitis can result from delayed or inadequate treatment –
requires surgical debridement of necrotic bone
More common in children with sickle cell disease
Pyomyositis
Purulent muscle abscesses.
Psoas abscess can be complication of TB spine
Rheumatic fever
Migratory arthritis, heart murmur
Gynecologic Syndromes
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Fever, pelvic pain, vaginal discharge
PID
Cervical motion tenderness, lower abdominal tenderness, vaginal
discharge
Tubo-ovarian abscess
Complication of untreated PID
Unilateral adnexal mass
Postpartum endometritis
Foul lochia, uterine tenderness following delivery
Most deliveries are performed outside of a hospital setting
Septic abortion
Abortion attempted in unsanitary conditions, unsterilized instruments.
Open cervix, vaginal bleeding, and purulent discharge
Treatment Limiting Factors
Self-treatment with OTC antibiotics
Limited spectrum of antibiotics
No health insurance
Counterfeit drugs and adulteration
References
1. Nadjm B, Mtove G, Amos B, et al. Severe febrile illness in adult hospital
admissions in Tanzania: a prospective study in an area of high malaria
transmission. Trans R Soc Trop Med Hyg 2012;106:688-95.
2. Bottieau E, Clerinx J, Colebunders R, Van Gompel A. Fever after a stay in
the tropics. Acta Clin Belg 2002;57:295-308.
3. Bottieau E, Clerinx J, Van den Enden E, et al. Fever after a stay in the
tropics: diagnostic predictors of the leading tropical conditions. Medicine
(Baltimore) 2007;86:18-25.
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Syndromic Approach to Fever in the Tropics
Syndrome
Fever alone
Neurologic
Abdominal
Pulmonary
Rash
Hemorrhage
(Danger!)
Bone and joint
Gynecologic
Diseases
Malaria
Typhoid
HIV
Dengue
Leptospirosis
Rickettsia
Relapsing fever
Other viral illness
Cerebral malaria
Meningitis
Encephalitis
HIV
Typhoid
Infectious colitis
Amebic liver abscess
Abdominal tuberculosis
Appendicitis
Pyelonephritis
HIV
Pneumonia
Pulmonary tuberculosis
HIV
Measles
HIV
Dengue
Other viruses
Ebola, Lassa, Marburg
Yellow fever
Dengue
Meningococcemia
Relapsing fever
Sickle cell disease
Septic arthritis
Osteomyelitis
Pyomyositis
Rheumatic fever
PID
Tubo-ovarian abscess
Endometritis
Septic abortion
Key Features / Clues
Pallor, malaria on blood smear
>1 week, abdominal pain, positive blood culture
>1 month, weight loss, positive HIV serology
Marked myalgia, eye pain, rash, ↓WBC, ↓plts
Fresh water exposure, conjunctival injection
Painless eschar
Eschar, lice, blood spirochetes
<1 week
Non-immune, malaria on blood smear
Nuchal rigidity, epidemic, CSF pleocytosis/organisms
Dog bite (rabies)
Dementia, focal neurologic signs
Ileal perforation with peritonitis
Bloody diarrhea, fecal WBCs or ameba
RUQ tenderness, ultrasound mass
Ascites, distension, wasting
RLQ tenderness
Dysuria, flank pain, urine WBCs
Diarrhea >1 month, weight loss
Tachypnea in child, chest retractions
Cough >1 month, hemoptysis, sputum AFB
Cough >1 month, positive HIV serology
Cough, conjunctivitis, coryza
Pruritus, vesicles, purple nodules, Stevens-Johnson
Islands of normal skin
Sore throat
Jaundice
Petechiae
Epidemic
Eschar, lice, jaundice, blood spirochetes
Family history, pain crisis, sickle prep
Purulent joint fluid
Skin drainage, sickle cell disease
Purulent muscle abscess
Migratory arthritis, heart murmur
Cervical motion tenderness
Adnexal mass
Post-partum, foul lochia, uterine tenderness
Open cervix, vaginal bleeding and purulent discharge
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